Sheet separator



Nov. 12, 1968 E. TIGER ET AL 3,410,551

SHEE TTTTTT 0R M kid lu A 37 NNNNN RS: 38 39 24 5 EM IGER ER E G. AN 33KENNET R CK 3| BY I 32 I I \Lz W Nov. 12, 1968 E. TIGER ET AL 3,410,551

7 SHEET SEPARATOR Filed March '7, 1966 2 Sheets-Sheet 2 INVENTORS: EMILTIGER ERSKINE G. CORMAN 'if ENNETH R. REICK ATT'YS United States Patent3,410,551 SHEET SEPARATUR Emil Tiger, Highland Park, Erskine G. Corman,Forest Park, and Kenneth R. Reick, Downers Grove, 1th., assignors toFormfoto Manufacturing Company, Addison, 111., a corporation of IllinoisFiied Mar. 7, 1966, Ser. No 532,396 6 Claims. (Cl. 271--64) ABSTRACT OFTHE DISCLOSURE A sheet separator for an electrostatic copying machine orthe like wherein the original and copy are fed together into the machinein generally aligned fashion-particularly as to the leading edges. Theseparator includes an electromechanical arrangement in which two rollerscoact to develop a shingling of the sheets by temporarily retarding onesheet through braking one of the rollers. This causes the retarded sheetto hump and the humping is utilized to release the braked roller. Theshingled sheets thereafter pass through the nip between the rollers andare separated by a second roller set.

Background of invention The invention finds particular utility inconnection with a wet process wherein the copy, after being exposed tothe images carried by the master, is subsequently developed by immersionwithin a fluid reservoir. In the past, this has required that the twosheets, is. the master and copy, be separated, and this has requiredeither manual manipulation on the part of an operator, shingling of thesheets or special sheet material-such as having oversized copy sheets soas to facilitate mechanical separation. The prior are has not realizedthe ultimate in this fieldthe ability to separate substantially alignedsheets. The difficulty of paperseparation is substantially increased bythe fact that in an electrostatic copier the sheets are attracted toeach other by the electrostatic charges resulting from the procedure.

It is, therefore, a principal object of the invention to provide a novelarrangement for achieving the separation of sheets, more particularlythose utilized in copy machines.

Other objects and advantages of the invention may be seen in the detailsof construction and operation set down in this specification.

The invention is described in conjunction with an illustrativeembodiment in the accompanying drawing, in

which- 7 FIG. 1 is a perspective view of apparatus embodying theteachings of the invention, the apparatus being partially broken away toreveal certain details of construction;

FIG. 2 is a sectional schematic view such as would be seen generallyalong the sight line 2-2 applied to FIG. 1;

FIG. 3 is an enlarged fragmentary sectional view of the upper right-handportion of FIG. 2 and showing the elements thereof in a certain initialstage of operation;

FiIGS. 4-6 are views essentially similar to that of FIG. 3 but showingthe apparatus therein in subsequent stages of operation; and

FIG. 7 is a wiring diagram of the electrical circuitry andelectromechanical elements associated with the apparatus of theremaining views.

In the illustration given and with particular reference to FIG. 1, thenumeral 10 designates generally a casing for an electrostatic copyapparatus and which is intended for desk or table mounting. The unit isrelice ati'vely compact and is characterized by an inlet slot 11 intowhich generally aligned superposed sheets are introduced for the purposeof copying. After the copying has been achieved, the original or masteris delivered from the slot 12 (see the extreme upper right-hand portionof FIG. 1) for receipt on an integral platform designated 13. The copysheet itself is returned through a discharge slot designated 14 in FIG.1.

The general procedure for preparing a copy of a master can beappreciated from a consideration of FIG. 2, and for a generalizedunderstanding of the overall operation of the electrostatic copyapparatus, the following is set down:

General description Referring to FIG. 2, the casing is again designated19 and is seen to include a corona charging device generally designated15. The corona charging device has an interior passage as at 16 throughwhich the generally aligned sheets pass in order to receive anelectrostatic charge which is required for electrostatic copying. Acorona charging device suitable for this purpose is shown and describedin our co-pending application, Ser. No. 503,773, filed Oct. 23, 1965,and reference may be had thereto for additional details.

For advancing the aligned sheets M and C (see FIG. 3) an interior frame17 (see FIG. 2) supports two sets of pull rolls 18 and 19, and 20 and21. These rolls serve to advance the aligned sheets along a path whichfirst includes the passage 16 of the corona device 15. The rolls 1821are rotated by means of a motor M (see FIG. 7) and a chain linkagesystem to be described in greater detail hereinafter.

Thereafter, under the influence of the pull rolls 20 and 21 and adifferent set of pull rolls 22 and 23, the aligned sheets are passedthrough an illumination means generally designated 24 (see also FIG. 7)and which includes essentially a source of light so as to pass rays oflight through the master M onto the electrostatically-charged copy sheetC. The aligned sheets, after exposure, are separated according to theapparatus to be described hereinafter, with the master issuing through apassage 12a leading to the slot 12, while the copy C is directed into areservoir generally designated 25 for development. A final set of pullroll-s 26 and 27 operate to advance the copy toward the discharge slot14 while squeezing most of the developing fluid from the copy C. Thespecific separation procedure and apparatus will now be described, andwith particular reference to FIGS. 3-6.

In FIG. 3, the aligned sheets M and C are seen positioned within the nip2S defined by rollers 29 and 30. Roller 30 is a driven roller, whileroller 29 is an idler. Rollers 29 and 30 are centrally annularlyrecessed as at 2911 and 30a to accommodate a switch 31 (see FIGS. 2 and7). As the forward edges of the sheets M and C engage the blade of theswitch 31, the same is moved slightly to the right in FIG. 3, energizingthe solenoid 32 (see FIGS. 1 and 7) which stops the idler roller 29 bymeans of brake 32a coupled to solenoid 32 by link 32b.

As the idler roller 29 is stopped, the master M is caused to hump in thefashion seen in FIG. 4. This results from the continued advancement ofthe copy C under the influence of the continued rotation of the pullroller 30, while the master M is restrained by the lack of rotation inthe idler roller 29. After a predetermined time, the hump M reaches theheight seen in FIG. 4this stemming from the continued rotation of thepull rollers 22, 23 and 30-so that the hump portion M contacts andactuates a blade switch 33. The blade switch 33 (as will be describedhereinafter relative to FIG. 7) releases the brake 32a associated withthe solenoid 32, permitting the idler roller 29 to recommence rotation.This results in the shingled or offset effect of the two sheets, as isseen in FIG. 5. The hump M continues to exist, but, in effect, movesrearwardly of the leading portion of the sheet M as the latter is nowadvanced under the joint rotation of the rollers 29 and 30. Ultimately,the now-offset sheets M and C reach rolls 34 and 35 (see FIG. 5), theserolls having been stopped by virtue of actuation of switch 31.

As the leading edge of the sheet C enters the nip 36 defined by therollers 34 and 35, the sheet C is caused to bulge or become displacedfrom its generally planar configuration seen in FIG. 5 to that seen inFIG. 6 and which is designated by the symbol C. This second bulging orbumping results in displacement of the leading edge M of the master soas to direct the master sheet M into the discharge passage 12a. Theretardation of the sheet C continues until the bulge portion C issufficiently great as to contact a switch blade 37 which is operative torestart the rolls 35 and 34 so as to direct the copy C to the reservoirwhere the electrostatic image is developed. A suitable reservoir isshown and described in our co-pending application, Ser. No. 503,064,filed Oct. 23, 1965, and reference may be had thereto for additionaldetails.

It will be seen that the invention is advantageous in that no matter howcarefully aligned the copy and master sheets may be at the outset, thereis a quick and positive mechanical separation without the need for anintervening human agency. Ordinarily, a secretary or clerk will, inpreparing sheets for copy work, generally align the same by tapping theleading edges on a desk or other surface so that, in the past, it hasbeen quite diflicult to develop some kind of offset or shingling so asto facilitate mechanical separation. This normal tendency can betolerated in the practice of the invention, and further is used toadvantage because the copy sheet now can be exactly the size of themaster.

Operation In the practice of the invention, the two generally alignedsheets M and C are advanced along a copying path through the coronadevice 15 and past the light source 24. Each of these may beelectrically energized by the arrangement depicted schematically in FIG.7. There, a plug 38 is adapted to be coupled to a source of and themachine is controlled by an ON-OFF switch 39.

Movement of the aligned sheets along the copy path is achieved frompower derived from motor M which, like the light source 24 and coronadevice 15, is disposed across the lines L and L of the diagram of FIG.7. The output of the motor M is delivered to a sprocket 40 (FIG. 1)which is coupled by means of a chain 41 to a driven sprocket b fixed tothe driven roller 30. Directionproviding idler sprockets 42 and 43 arealso seen in FIG. 1. From these, rotational power is delivered by achain and sprocket system (on the hidden side of the device in FIG. 1)to the pull rolls 18-23 and 26 and 27.

These pull rolls 18-23 deliver the aligned sheets to the nip 28 definedby the rollers 29 and 30 which constitute a retarding means for one ofthe aligned sheets. The retarding action is initiated by engagement ofthe leading edges of the sheets M and C with the spring loaded blade ofthe switch 31. When the switch 31 is actuated-by sensing the leadingedges, the switch delivers power to the solenoid 32. v

The solenoid 32 then acts to retract link 32b to engage brake 32a withthe journal of idler roller 29, thus temporarily stopping the same. Thecessation of rotation of the roll 29 results in a flexure ordisplacement, hereinbefore referred to as the hump M, which is thensensed by the switch 33 to limit the degree of flexing the sheet.

The actuation of switch 33 breaks the circuit to solenoid 32 (switch 31still being in its current-delivering position by virtue of the factthat the sheet C in passing through the nip 28 toward rolls 34 and 35continues to depress the sensing blade of switch 31). Thus, the switch33 constitutes a control means for superceding the retardation 4occasioned by the sensing of the position of sheets M and C by theswitch 31.

It will also be seen that the rolls 34 and 35 constitute secondretarding means for the now-offset sheets C and M as seen in FIG. 5.Further, we find it advantageous to provide a guide plate in the form ofthe plate 44 which insures that the offset sheets, particularly thesheet C, is directed into the nip 36, and further that the bulging thatresults from the leading edge of the sheet C being positioned within thenip 36 will occur in the direction shown in FIG. 6 and wherein theswitch 37 is arranged for sensing the sheet flexure.

The rolls 34 and 35 are driven by motor M (see FIG. 7). At the outset ofoperation the motor M is operating due to flow of current throughswitches 37, 33 and 31. Thus, even before the aligned sheets enter thecorona device 15, the rolls 34 and 35 are rotating and continue to do sountil switch 31 is tripped by the leading edges of the sheets M and C.Thereafter, the rolls 34 and 35 stop until the second hump appearstoactuate switch 37. This re-enengizes motor M independently of switches33 and 31. By the time this second hump M disappears, indicating thecompletion of the engagement of the trailing portions of the sheets Mand C with the rollers 29 and 30, the switch 37 returns to its normalposition shown in FIG. 7. This arrangement then results in deliveringcurrent to motor M through switches 31 and 33, these again being intheir ready conditions due to the fact that the trailing portions of thesheets M and C are no longer able to actuate these switches. Switch 37,as it starts motor M also de-energizes solenoid 32 so that when hump Mcollapses at the tail end of sheets M and C, it will prevent there-energizing of solenoid 32. If solenoid 32 was re-enerlgized by switch33 when hump M collapsed roller 29 would stop again and prevent freedelivery of the tail end portions of sheets M and C.

While in the foregoing specification, we have set down certain detailsfor the purpose of explanation, many variations therein may be madewithout departing from the spirit and scope of the invention.

We claim:

1. A sheet separator, comprising a frame, means on said frame foradvancing along a predetermined path a pair of relatively flexiblesheets in surface contact and generally aligned relation, first means onsaid frame in said path for temporarily retarding one of said sheetsrelative to the other to provide the leading edge portion of said othersheet projecting forwardly in the direction of path advance, and secondmeans on said frame in said path for temporarily retarding the leadingedge of said other sheet, whereby a portion of said other sheet rearwardof its leading edge is flexed generally normal to said path to projectthe leading edge of said one sheet out of said path, said firstretarding means including roller means adapted to flex a portion of saidone sheet in a direction generally normal to said path, sensing means onsaid frame responsive to the flexing of said one sheet for actuatingsaid roller means to develop only a limited flexing in said one sheet.

2. The structure of claim 1 in which said first retarding means alsoincludes switch means responsive to the generally aligned leading edgesof said sheets, said roller means including a pair of rollers defining anip, means on said frame for rotating said rollers, one of said rollersbeing adapted to contact said one sheet, the other of said rollers beingadapted to contact the other sheet, said switch means being operativelyassociated with said one roller to stop rotation of the same in responseto a predetermined position of said generally aligned leading edges,said sensing means also being operatively associated with said oneroller to actuate the same by restarting rotation thereof.

3. The structure of claim 1 in which said second retarding meansincludes a pair of rolls arranged in sideby-side relation to define anip, means on said frame for rotating said rolls, and switch meansoperatively associated lWith said rolls for stopping rotation thereofprior to entry into said nip of said other sheet leading edge, andsensing means responsive to said flexed portion to restart rotation ofsaid rollers.

4. The structure of claim 3 in which said frame is equipped with asupport for guiding said other sheet leading edge into said nip.

5. A sheet separator comprising a frame, roll means on said frame foradvancing a pair of generally aligned contacting sheets into the nipdefined by a pair of rollers, a pair of rollers mounted for rotation insaid frame and defining said nip, means on said fname for rotating saidrollers, means on said frame responsive to the position of said sheetsrelative to said nip for stopping the rotation of one of said rollers tocreate a fiexure, the one of said sheets contacting said one roller,sensing means adjacent said one roller responsive to the degree offlexure of said one sheet for re-starting the rotation of said oneroller whereby said sheets are thereafter advanced with their leadingedges in shingled relation, and means on said frame in the path ofsheets leaving asid pair of rollers for temporarily retarding theleading edge of the more advanced sheet to eifect separation of thesheets.

6. The structure of claim 5 in which the other of said rollers iscoupled to said rotating means, said one roller being frictionallydriven by said other rollers, and brake means operatively associatedwith said responsive means for stopping the frictional drive of said oneroller, said sensing means also being operatively associated with saidswitoh means for deactivating said brake trneans.

References Cited UNITED STATES PATENTS JOHN M. HORAN, Primary Examiner.

